CincyKidsRad

Cincinnati Children's Radiology

Carpal coalition

AP radiograph of the hand and wrist shows considerable deformity with fusion of all of the carpal bones and absence of the metacarpals and phalanges. Only soft tissue stubs are present for fingers. Carpal coalition occurs in up to 1% of the population. However, the incidence is variable depending on the segment of the population studied. The most common carpal coalition is a lunotriquetral coalition. This type of complex coalition affecting both the proximal and distal row and inclusive of all of the carpal bones is rare.

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AP x-ray of the foot and lateral x-ray of the ankle shows coalition (arrow) of the medial cuneiform and the navicular bone. A coalition is an abnormal bridging of the bones. It is usually congenital. The most common site of a coalition in the feet is either between the calcaneus and the navicular or between the calcaneus and the talus.

AP x-ray of the wrist shows lunotriquetral coalition. Carpal coalition is more common in women and African Americans. Coalition of the proximal carpal row is usually an incidental finding while coalitions in the distal carpal row are more commonly associated with syndromes.

Scaphoid view of the wrist shows a coalition (arrow) of the trapezium and trapezoid bones. Carpal coalitions occur as a result of failure of the normal segmentation of the carpal mesenchyme. The most common carpal coalition is between the lunate and triquetrum followed by the capitate and hamate.

AP radiograph of the hand shows a coalition (arrow) between the lunate and triquetrum. This is the most common coalition of the wrist occurring with a prevalence of 0.1%. Patients with a lunotriquetral coalition are typically asymptomatic. Occasionally, patients may present with ulnar-sided wrist pain.